Add Cypress E2E test of general room settings tab with Percy snapshots

[luixxiul]

Closes element-hq/element-web#25452

This PR suggests to add general-room-settings-tab.spec.ts for the room settings tab (General) with Percy snapshots to capture visual regressions like element-hq/element-web#25451 and element-hq/element-web#25455.

It is expected that the Percy will not take the snapshots as expected until #10947 is merged. Once it is merged, Percy should be able to take snapshots like below (with local addresses area collapsed and expanded):

type: task

Signed-off-by: Suguru Hirahara [email protected]

Checklist

• Tests written for new code (and old code if feasible)
• Linter and other CI checks pass
• Sign-off given on the changes (see CONTRIBUTING.md)

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This change is marked as an internal change (Task), so will not be included in the changelog.

[robintown]

Thank you, this is really helpful.

[luixxiul]

The snapshots were taken here:

• https://percy.io/dfde73bd/matrix-react-sdk/builds/27976934/changed/1555735198?browser=firefox&browser_ids=36%2C38%2C39&subcategories=unreviewed%2Cchanges_requested&viewLayout=side-by-side&viewMode=new&width=796&widths=580%2C796%2C1024%2C1920
• https://percy.io/dfde73bd/matrix-react-sdk/builds/27976934/changed/1555735197?browser=firefox&browser_ids=36%2C38%2C39&subcategories=unreviewed%2Cchanges_requested&viewLayout=side-by-side&viewMode=new&width=796&widths=580%2C796%2C1024%2C1920

As noted above, the Percy will not take the snapshots as expected until #10947 is merged.